The firm forecasts insured losses of $7.5-$10bn for the Camp wildfire, and $1.5-$3bn for the Woolsey Fire, which are together thought to have been responsible for at least 80 deaths.

Almost 1,000 people remain missing after the two fires burned a combined 245,000 acres of land and destroyed more than 12,000 homes and businesses.

This is the second consecutive wildlife season believed to have cost insurers more than $10bn, with the Camp Fire the most deadliest and destructive recorded in Californian history.

“Wildfire is now a major catastrophe risk that must be rigorously managed with the best data and model science,” RMS chief risk modelling officer, Mohsen Rahnama, said.

“With increasing exposure due to properties near wildland areas and ongoing climate variability, insurers, policymakers, and homeowners must adapt to the prospect of more frequent and severe wildfires.”

The Camp and Woolsey wildfires are among 15 that broke out earlier this month, with the former burning 11,000 structures and responsible for at least 77 fatalities

Both spread quickly due to low moisture, abnormally high temperatures, dry vegetation, and intense seasonal winds, with the Woolsey Fire burning more than 1,450 high value properties and killing three.

The insured loss estimates are derived from RMS modelling that simulates the ignition, fire spread, ember accumulations, and smoke dispersion of the wildfires.

The findings are supported by damage reports from the California Department of Forestry and Fire Protection as of 18 November, observations from displaced residents, and information from firefighting personnel.

“We are confident the model will contribute to the creation of safer communities that promote fire safety and awareness,” Rahnama said.

“In the wake of consecutive record-breaking wildfire seasons, we are hopeful that more focus will be placed on fire mitigation, safe construction practices, and community resilience.”